On Monday, Mason and the couple's three young children placed flowers and flags at a memorial outside the dispensary.

"It's hard," she said, wiping away tears. "I try not to cry in front of the kids."

The 4-year-old twins were wearing Dallas Cowboys hats that were much too big. The hats belonged to their dad.

Mason said she has tried to explain to the twins why their dad did not come home.

"They know the bad guys hurt daddy and that's why Jesus had to take him to heaven," she said.

The couple who found Mason said they just happened to be driving by Saturday night around 9:45 p.m. when they saw the dispensary door wide open and a man laying in the door. They tried to help and called police.

"He was just trying to provide for his kids and in the middle of that he gets shot," said the woman, who did not want to be identified. "I don't know who would kill a guy that was just trying to do his job."

Mason's wife said they had both dreamed of becoming police officers and last week were notified they were eligible to take the Denver police test. She said her husband was working two jobs to support the family.

Police described the suspects as two black males armed with handguns. Police are offering a $12,000 reward and ask anyone with information to call them.